The present invention relates to a storage register for propagating magnetic domains in a propagation channel comprising an insulating substrate, a soft magnetic layer overlying the insulating substrate, in which is formed the propagation channel, a hard magnetic layer overlying the soft magnetic layer, except in the areas defining the propagation channel, an insulating layer overlying the soft and hard magnetic layers, a shift conduction layer in a Greek border pattern overlying the insulating layer, constituted by parallel segments perpendicular to the propagation channel, the propagation channel comprising a writing box, upstream the propagation channel, a reading box, downstream the propagation channel, narrow zones for the storage of the domains, widened boxes for the growth of the domains.
A register of this type has been described in particular in U.S. Pat. No. 4,250,566.
The present invention relates more particularly to the reading of the domains at the downstream end of the propagation channel, for example by means of reading magnetoresistor disposed on the reading box of the propagation channel.
As soon as these storage registers appeared, it was already sought to obtain a maximum reading level with, to this end, an enlarged, or widened, reading box and a register structure allowing the domains to split and, consequently, allowing this reading box to be filled with a likewise increased domain, the reading level depending on the quantity of magnetostatic charges at the downstream end of the domain.
The split of the domains into a determined number of domains, obviously along the difficult axis of the soft layer, and therefore the filling of the reading box with a plurality of domains, is already advantageous. In fact, as the time for the domains to grow perpendicularly to the propagation channel, is much longer than the time for the domains to grow by the points, i.e. in the direction of the propagation channel, the reading time, in this case, compared with that which is necessary when the reading box is filled only with one increased domain by the shift conductor, is divided by a number equal to the quantity of the split domains.
In addition, the split of the domains makes it possible not to cause the shift and increasing conductor to pass over the reading box, and consequently enables the reading magnetoresistor to be disposed on the reading box, at the same level as the shift conductor.
However, this domain split must be effected via increasing boxes. Now, the structure of heretofore known registers was such that the self erasion of these intermediate increasing boxes could not be envisaged and that either erasion conductors had to be provided or, preferably, a simple erasion conductor but with a plurality of consecutive segments in the same direction above these intermediate boxes. Even if the shift conductor served at the same time as erasion conductor, this raised a problem of topology, due to the multiple enclosure by the conductor of the output studs or terminals thereof. In any case, the increase of the domains in the intermediate increasing boxes also required a plurality of consecutive segments of the shift conductor in the same direction, to preserve the current density along the intermediate boxes. The known registers therefore raised this problem of topology.